In the evaluation of the condition of a critically ill patient, blood analysis plays a key role. Blood analysis may include the measurement of blood gas parameters like pH, PO2, pCO2, metabolic parameters like glucose and lactate, and electrolytes like sodium, potassium and chloride.
The analytic process of blood analysis, and in particular blood gas analysis, is an integrated process including the preanalytical phase, the analytical phase and the postanalytical phase. In order to obtain correct results from the analysis, proper handling of samples and data should be ensured in each of these phases.
Prior to analysis, a blood sample may coagulate or settle or the sample may react with air in the blood sampler. In particular for blood gas analysis, the presence of air bubbles may bias the results and should be avoided. Often, an anticoagulant is added to the blood sample, and the sample is thoroughly stirred before analysis. The purpose of the stirring of blood samples is at least two-fold: It facilitates the dissolution of anticoagulant, e.g. heparin, added to the blood sample, and it prevents settling. Failure to properly dissolve the heparin may lead to formation of micro clots, which in turn may bias results and/or damage the analyzer. Settling may lead to sample inhomogeneity and misleading analytical results.
Traditionally, sample maintenance by stirring of samples for blood analysis is done manually by repeatedly inverting the sampler and by rolling it horizontally. A stirring element may be introduced into the sampler to improve stirring when shifted back and forth in the sampler. In this way, stirring is done without introducing any air into the sampler.
An example of an integrated analytical system for blood analysis is disclosed in U.S. Pat. No. 5,366,896. U.S. Pat. No. 5,366,896 discloses an integrated analytical system with a plurality of remote laboratories and a central monitoring station for the analysis of blood samples. The system includes a sample storage rack in which a plurality of blood sample containing syringes may be arranged and rotated for sample maintenance. Subsequent to rotation, syringes are automatically transferred to an analysis section of the analytical system for sample analysis. The rotational mixing disclosed in U.S. Pat. No. 5,366,896, however, is insufficient to ensure homogeneity of a blood sample.
Thus, despite the hitherto proposed blood analyzers, there is still a need for a blood analyzer which provides handling and analysis of blood samples for blood analysis. Further, there is a need for a sample handler providing handling of blood samples for blood analysis.